problem with .DLL files

I tried to install a game on my computer and ever since I have had problems. Windows Media Player won’t work and a lot of my other games won’t work either. They all keep saying that a dsound.dll, ddraw.dll, and a couple of other .dll files are missing. I can’t reboot the computer. we had a burner installed and something about they took out the drive that you reboot with to put the buner in. So, what other options do I have? What can I do to fix it? Is there somewhere where I can get a disk withthese .dll files? I don’t know a whole lot about computers soI need all the help I can get. Thanks